diff --git a/web/projects/setup-wizard/src/app/pages/language.page.ts b/web/projects/setup-wizard/src/app/pages/language.page.ts
index b14cc3d0b..f30953d1e 100644
--- a/web/projects/setup-wizard/src/app/pages/language.page.ts
+++ b/web/projects/setup-wizard/src/app/pages/language.page.ts
@@ -122,13 +122,13 @@ export default class LanguagePage {
 
   constructor() {
     if (this.selected) {
-      this.i18nService.setLanguage(this.selected.name)
+      this.i18nService.setLang(this.selected.name)
     }
   }
 
   onLanguageChange(language: Language) {
     if (language) {
-      this.i18nService.setLanguage(language.name)
+      this.i18nService.setLang(language.name)
     }
   }
 
diff --git a/web/projects/shared/src/i18n/dictionaries/en.ts b/web/projects/shared/src/i18n/dictionaries/en.ts
index 1aef6d5e3..a2bc6e74b 100644
--- a/web/projects/shared/src/i18n/dictionaries/en.ts
+++ b/web/projects/shared/src/i18n/dictionaries/en.ts
@@ -56,7 +56,7 @@ export const ENGLISH = {
   'Beginning shutdown': 57,
   'Add': 58,
   'Ok': 59,
-  'french': 60,
+  'fr_FR': 60,
   'This value cannot be changed once set': 61,
   'Continue': 62,
   'Click or drop file here': 63,
@@ -462,10 +462,10 @@ export const ENGLISH = {
   'StartOS UI': 485,
   'WiFi': 486,
   'Documentation': 487, // as in, a website to view documentation
-  'spanish': 488,
-  'polish': 489,
-  'german': 490,
-  'english': 491,
+  'es_ES': 488,
+  'pl_PL': 489,
+  'de_DE': 490,
+  'en_US': 491,
   'Start Menu': 492,
   'Install Progress': 493,
   'Downloading': 494,
@@ -670,9 +670,9 @@ export const ENGLISH = {
   'Preserve': 706,
   'Overwrite': 707,
   'Unlock': 708,
-  'Drive': 709, // as in, a storage device
+  'Drive': 709, // the noun, a storage device
   'Transfer': 710, // the verb
   'The list is empty': 711,
   'Restart now': 712,
   'Later': 713, // as in, (do it) later
-} as const
+} as Record<any, any>
diff --git a/web/projects/shared/src/i18n/i18n.providers.ts b/web/projects/shared/src/i18n/i18n.providers.ts
index cee7f1aa9..5aa38998c 100644
--- a/web/projects/shared/src/i18n/i18n.providers.ts
+++ b/web/projects/shared/src/i18n/i18n.providers.ts
@@ -6,7 +6,7 @@ import {
   TuiLanguageSwitcherService,
 } from '@taiga-ui/i18n'
 import { ENGLISH } from './dictionaries/en'
-import { i18nService } from './i18n.service'
+import { i18nService, Languages } from './i18n.service'
 
 export type i18nKey = keyof typeof ENGLISH
 export type i18n = Record<(typeof ENGLISH)[i18nKey], string>
@@ -20,7 +20,7 @@ export const I18N_LOADER = new InjectionToken<
 >('')
 
 export const I18N_STORAGE = new InjectionToken<
-  (lang: TuiLanguageName) => Promise<void>
+  (lang: Languages) => Promise<void>
 >('', {
   factory: () => () => Promise.resolve(),
 })
diff --git a/web/projects/shared/src/i18n/i18n.service.ts b/web/projects/shared/src/i18n/i18n.service.ts
index b627cddbf..28f1bc86a 100644
--- a/web/projects/shared/src/i18n/i18n.service.ts
+++ b/web/projects/shared/src/i18n/i18n.service.ts
@@ -2,6 +2,20 @@ import { inject, Injectable, signal } from '@angular/core'
 import { TuiLanguageName, TuiLanguageSwitcherService } from '@taiga-ui/i18n'
 import { I18N, I18N_LOADER, I18N_STORAGE } from './i18n.providers'
 
+export const languages = ['en_US', 'es_ES', 'de_DE', 'fr_FR', 'pl_PL'] as const
+export type Languages = (typeof languages)[number]
+
+/**
+ * Maps POSIX locale strings to TUI language names
+ */
+export const LANGUAGE_TO_TUI: Record<Languages, TuiLanguageName> = {
+  en_US: 'english',
+  es_ES: 'spanish',
+  de_DE: 'german',
+  fr_FR: 'french',
+  pl_PL: 'polish',
+}
+
 @Injectable({
   providedIn: 'root',
 })
@@ -12,20 +26,32 @@ export class i18nService extends TuiLanguageSwitcherService {
 
   readonly loading = signal(false)
 
-  override setLanguage(language: TuiLanguageName = 'english'): void {
+  /**
+   * Current language as POSIX locale string
+   */
+  get lang(): Languages {
+    return (
+      (Object.entries(LANGUAGE_TO_TUI).find(
+        ([, tui]) => tui === this.language,
+      )?.[0] as Languages) || 'en_US'
+    )
+  }
+
+  setLang(language: Languages = 'en_US'): void {
+    const tuiLang = LANGUAGE_TO_TUI[language]
     const current = this.language
 
-    super.setLanguage(language)
+    super.setLanguage(tuiLang)
     this.loading.set(true)
 
-    if (current === language) {
-      this.i18nLoader(language).then(value => {
+    if (current === tuiLang) {
+      this.i18nLoader(tuiLang).then(value => {
         this.i18n.set(value)
         this.loading.set(false)
       })
     } else {
       this.store(language).then(() =>
-        this.i18nLoader(language).then(value => {
+        this.i18nLoader(tuiLang).then(value => {
           this.i18n.set(value)
           this.loading.set(false)
         }),
@@ -33,12 +59,3 @@ export class i18nService extends TuiLanguageSwitcherService {
     }
   }
 }
-
-export const languages = [
-  'english',
-  'spanish',
-  'polish',
-  'german',
-  'french',
-] as const
-export type Languages = (typeof languages)[number]
diff --git a/web/projects/shared/src/util/languages.ts b/web/projects/shared/src/util/languages.ts
index b2b24c78a..baf1e03a4 100644
--- a/web/projects/shared/src/util/languages.ts
+++ b/web/projects/shared/src/util/languages.ts
@@ -18,22 +18,22 @@ export interface Language {
  * Available languages with their metadata
  */
 export const LANGUAGES: Language[] = [
-  { code: 'en', name: 'english', nativeName: 'English' },
-  { code: 'es', name: 'spanish', nativeName: 'Español' },
-  { code: 'de', name: 'german', nativeName: 'Deutsch' },
-  { code: 'fr', name: 'french', nativeName: 'Français' },
-  { code: 'pl', name: 'polish', nativeName: 'Polski' },
+  { code: 'en', name: 'en_US', nativeName: 'English' },
+  { code: 'es', name: 'es_ES', nativeName: 'Español' },
+  { code: 'de', name: 'de_DE', nativeName: 'Deutsch' },
+  { code: 'fr', name: 'fr_FR', nativeName: 'Français' },
+  { code: 'pl', name: 'pl_PL', nativeName: 'Polski' },
 ]
 
 /**
- * Maps i18n language names to ISO language codes
+ * Maps POSIX locale strings to ISO language codes
  */
 export const LANGUAGE_TO_CODE: Record<Languages, LanguageCode> = {
-  english: 'en',
-  spanish: 'es',
-  german: 'de',
-  french: 'fr',
-  polish: 'pl',
+  en_US: 'en',
+  es_ES: 'es',
+  de_DE: 'de',
+  fr_FR: 'fr',
+  pl_PL: 'pl',
 }
 
 /**
diff --git a/web/projects/ui/src/app/app.component.ts b/web/projects/ui/src/app/app.component.ts
index 0c359da07..1ef65c6fb 100644
--- a/web/projects/ui/src/app/app.component.ts
+++ b/web/projects/ui/src/app/app.component.ts
@@ -42,6 +42,6 @@ export class AppComponent {
     .watch$('serverInfo', 'language')
     .pipe(takeUntilDestroyed())
     .subscribe(language => {
-      this.i18n.setLanguage(language || 'english')
+      this.i18n.setLang(language || 'en_US')
     })
 }
diff --git a/web/projects/ui/src/app/routes/portal/routes/system/routes/general/general.component.ts b/web/projects/ui/src/app/routes/portal/routes/system/routes/general/general.component.ts
index d77640356..3adf6fc83 100644
--- a/web/projects/ui/src/app/routes/portal/routes/system/routes/general/general.component.ts
+++ b/web/projects/ui/src/app/routes/portal/routes/system/routes/general/general.component.ts
@@ -19,13 +19,13 @@ import {
   i18nService,
   Keyboard,
   KeyboardCode,
-  languages,
-  Languages,
+  Language,
+  LANGUAGES,
   LANGUAGE_TO_CODE,
   LoadingService,
 } from '@start9labs/shared'
 import { TuiResponsiveDialogService } from '@taiga-ui/addon-mobile'
-import { TuiAnimated, TuiContext, TuiStringHandler } from '@taiga-ui/cdk'
+import { TuiAnimated } from '@taiga-ui/cdk'
 import {
   TuiAppearance,
   TuiButton,
@@ -110,20 +110,16 @@ import { KeyboardSelectComponent } from './keyboard-select.component'
         <tui-icon icon="@tui.languages" />
         <span tuiTitle>
           <strong>{{ 'Language' | i18n }}</strong>
-          <span tuiSubtitle [style.text-transform]="'capitalize'">
-            @if (language; as lang) {
-              {{ lang | i18n }}
-            } @else {
-              {{ i18nService.language }}
-            }
+          <span tuiSubtitle>
+            {{ currentLanguage?.nativeName }}
           </span>
         </span>
         <button
           tuiButtonSelect
           tuiButton
           [loading]="i18nService.loading()"
-          [ngModel]="i18nService.language"
-          (ngModelChange)="i18nService.setLanguage($event)"
+          [ngModel]="currentLanguage"
+          (ngModelChange)="onLanguageChange($event)"
         >
           {{ 'Change' | i18n }}
           <tui-data-list-wrapper
@@ -131,9 +127,12 @@ import { KeyboardSelectComponent } from './keyboard-select.component'
             new
             size="l"
             [items]="languages"
-            [itemContent]="translation"
+            [itemContent]="languageContent"
           />
         </button>
+        <ng-template #languageContent let-item>
+          {{ item.nativeName }}
+        </ng-template>
       </div>
       <div tuiCell tuiAppearance="outline-grayscale">
         <tui-icon icon="@tui.monitor" />
@@ -297,17 +296,14 @@ export default class SystemGeneralComponent {
   readonly score = toSignal(this.patch.watch$('ui', 'snakeHighScore'))
   readonly os = inject(OSService)
   readonly i18nService = inject(i18nService)
-  readonly languages = languages
-  readonly translation: TuiStringHandler<TuiContext<Languages>> = ({
-    $implicit,
-  }) => {
-    const [head = '', ...result] = this.i18n.transform($implicit) || ''
+  readonly languages = LANGUAGES
 
-    return [head.toUpperCase(), ...result].join('')
+  get currentLanguage(): Language | undefined {
+    return LANGUAGES.find(lang => lang.name === this.i18nService.lang)
   }
 
-  get language(): Languages | undefined {
-    return this.languages.find(lang => lang === this.i18nService.language)
+  onLanguageChange(language: Language) {
+    this.i18nService.setLang(language.name)
   }
 
   // Expose shared utilities for template use
diff --git a/web/projects/ui/src/app/services/api/mock-patch.ts b/web/projects/ui/src/app/services/api/mock-patch.ts
index 86e124d8a..06b1ef711 100644
--- a/web/projects/ui/src/app/services/api/mock-patch.ts
+++ b/web/projects/ui/src/app/services/api/mock-patch.ts
@@ -219,7 +219,7 @@ export const mockPatchData: DataModel = {
     ram: 8 * 1024 * 1024 * 1024,
     devices: [],
     kiosk: true,
-    language: 'english',
+    language: 'en_US',
     keyboard: {
       layout: 'us',
       model: null,